codegen: Add the :execresult query annotation (#542)

Author: kyleconroy

docs/annotations.md

@@ -65,6 +65,22 @@ func (q *Queries) DeleteAuthor(ctx context.Context, id int64) error {
 }
 ```
 
+### `:execresult`
+
+The generated method will return the [sql.Result](https://golang.org/pkg/database/sql/#Result) returned by
+[ExecContext](https://golang.org/pkg/database/sql/#DB.ExecContext).
+
+```sql
+-- name: DeleteAllAuthors :execresult
+DELETE FROM authors;
+```
+
+```go
+func (q *Queries) DeleteAllAuthors(ctx context.Context) (sql.Result, error) {
+  return q.db.ExecContext(ctx, deleteAllAuthors)
+}
+```
+
 ### `:execrows`
 
 The generated method will return the number of affected rows from the

internal/codegen/golang/gen.go

@@ -11,6 +11,7 @@ import (
 
 	"github.com/kyleconroy/sqlc/internal/codegen"
 	"github.com/kyleconroy/sqlc/internal/config"
+	"github.com/kyleconroy/sqlc/internal/metadata"
 )
 
 type Generateable interface {
@@ -124,6 +125,11 @@ func interfaceImports(r Generateable, settings config.CombinedSettings) fileImpo
 	if uses("sql.Null") {
 		std["database/sql"] = struct{}{}
 	}
+	for _, q := range gq {
+		if q.Cmd == metadata.CmdExecResult {
+			std["database/sql"] = struct{}{}
+		}
+	}
 	if uses("json.RawMessage") {
 		std["encoding/json"] = struct{}{}
 	}
@@ -324,6 +330,11 @@ func queryImports(r Generateable, settings config.CombinedSettings, filename str
 	if uses("sql.Null") {
 		std["database/sql"] = struct{}{}
 	}
+	for _, q := range gq {
+		if q.Cmd == metadata.CmdExecResult {
+			std["database/sql"] = struct{}{}
+		}
+	}
 	if uses("json.RawMessage") {
 		std["encoding/json"] = struct{}{}
 	}
@@ -518,6 +529,9 @@ type Querier interface {
 	{{- if eq .Cmd ":execrows"}}
 	{{.MethodName}}(ctx context.Context, {{.Arg.Pair}}) (int64, error)
 	{{- end}}
+	{{- if eq .Cmd ":execresult"}}
+	{{.MethodName}}(ctx context.Context, {{.Arg.Pair}}) (sql.Result, error)
+	{{- end}}
 	{{- end}}
 }
 
@@ -684,6 +698,18 @@ func (q *Queries) {{.MethodName}}(ctx context.Context, {{.Arg.Pair}}) (int64, er
 	return result.RowsAffected()
 }
 {{end}}
+
+{{if eq .Cmd ":execresult"}}
+{{range .Comments}}//{{.}}
+{{end -}}
+func (q *Queries) {{.MethodName}}(ctx context.Context, {{.Arg.Pair}}) (sql.Result, error) {
+  	{{- if $.EmitPreparedQueries}}
+	return := q.exec(ctx, q.{{.FieldName}}, {{.ConstantName}}, {{.Arg.Params}})
+  	{{- else}}
+	return q.db.ExecContext(ctx, {{.ConstantName}}, {{.Arg.Params}})
+  	{{- end}}
+}
+{{end}}
 {{end}}
 {{end}}
 {{end}}

internal/endtoend/testdata/exec_result/endtoend.json

@@ -0,0 +1,4 @@
+{
+    "experimental_parser_only": true
+}
+  

internal/endtoend/testdata/exec_result/go/db.go

@@ -0,0 +1,4 @@
+CREATE TABLE bar (id serial not null);
+
+-- name: DeleteBarByID :execresult
+DELETE FROM bar WHERE id = $1;

internal/endtoend/testdata/exec_result/go/models.go

@@ -0,0 +1,12 @@
+{
+  "version": "1",
+  "packages": [
+    {
+      "path": "go",
+      "name": "querytest",
+      "schema": "query.sql",
+      "queries": "query.sql",
+      "emit_interface": true
+    }
+  ]
+}

internal/endtoend/testdata/exec_result/go/querier.go

@@ -14,6 +14,14 @@ const (
 	CommentSyntaxHash
 )
 
+const (
+	CmdExec       = ":exec"
+	CmdExecResult = ":execresult"
+	CmdExecRows   = ":execrows"
+	CmdMany       = ":many"
+	CmdOne        = ":one"
+)
+
 // A query name must be a valid Go identifier
 //
 // https://golang.org/ref/spec#Identifiers
@@ -47,15 +55,15 @@ func Parse(t string, commentStyle CommentSyntax) (string, string, error) {
 			part = part[:len(part)-1] // removes the trailing "*/" element
 		}
 		if len(part) == 2 {
-			return "", "", fmt.Errorf("missing query type [':one', ':many', ':exec', ':execrows']: %s", line)
+			return "", "", fmt.Errorf("missing query type [':one', ':many', ':exec', ':execrows', ':execresult']: %s", line)
 		}
 		if len(part) != 4 {
 			return "", "", fmt.Errorf("invalid query comment: %s", line)
 		}
 		queryName := part[2]
 		queryType := strings.TrimSpace(part[3])
 		switch queryType {
-		case ":one", ":many", ":exec", ":execrows":
+		case CmdOne, CmdMany, CmdExec, CmdExecResult, CmdExecRows:
 		default:
 			return "", "", fmt.Errorf("invalid query type: %s", queryType)
 		}